1. Field of the Invention
This invention relates to a shock absorber for a remote-controlled model car, particularly to one able to automatically adjust its buffering force to an excellent condition for matching with different-extent external forces, having an excellent effect in buffering and shock absorption.
2. Description of the Prior Art
A conventional shock absorber for a remote-controlled model car includes a hydraulic cylinder 10 and a spring member 20. The hydraulic cylinder 10 consists of a cylinder 11 and a piston rod 12. The cylinder 11 has its interior filled with liquid oil and the rod body 121 of the piston rod 12 has its upper end connected with a piston 123 with two flow-guiding holes 122 to be clogged in the interior of the cylinder 11. The spring member 20 is positioned between the upper spring holder 111 of the cylinder 11 and the lower spring holder 124 at the lower end of the piston rod 12. Thus, when the remote-controlled model car runs on an uneven road and sways up and down, the shock absorber of the remote-controlled model car will be actuated by an external force to make the cylinder 11 and the piston rod 12 push each other. At this time liquid oil in the cylinder 11 over the piston 123 will be compressed to flow to the cylinder 11 under the piston 123 through the two flow-guiding holes 122 of the piston 123, thus producing oil-buffering effect. The piston rod 12 is able to recover its original position by the resilience of the spring member 20.
However, the flow-guiding holes 122 of the piston 123 of a conventional shock absorber are fixed in size; therefore, the buffering force produced by the conventional shock absorber cannot be altered. In other words, the conventional shock absorber cannot automatically adjust its buffering force to a most appropriate condition in accordance with the condition of an uneven road or the extent of swaying. As a result, the shock absorber fails to produce a marked shock absorbing effect, or the buffering force produced is insufficient, likely to let the remote-controlled model car jump and sway up and down violently or collide with the ground and get damaged.